Characteristics of biochemical markers and quality parameters using whole wheat flours in Korean wheat cultivars and lines

Tese de doutoramento em Ciências e Tecnologias da Informação, apresentada ao Departamento de Engenharia Informática da Faculdade de Ciências e Tecnologia da Universidade de CoimbraO espectro rádio tem vindo a ser regulado de um modo estático. Ou seja, este encontra-se essencialmente dividido em bandas de frequência licenciadas, com utilização restringida a um número limitado de utilizadores autorizados, e em algumas bandas de frequência não licenciadas para utilização livre. Devido à falta de flexibilidade resultante desta abordagem, partes significativas do espectro rádio encontram-se subutilizadas. Em simultâneo, outras bandas de frequência estão a ficar cada vez mais saturadas, nomeadamente as não licenciadas em áreas densamente povoadas. O Rádio Cognitivo é um paradigma recente cujo objetivo é melhorar o nível de eficiência na utilização do espectro rádio. Os seus princípios gerais consistem em permitir que dispositivos sem fios não licenciados (os denominados Utilizadores Secundários) possam aceder às bandas de frequência licenciadas desde que estes não interferiram de forma prejudicial com os utilizadores licenciados (os denominados Utilizadores Primários). A abordagem preponderante na área de Rádio Cognitivo consiste em ter utilizadores secundários com capacidade para, de um modo dinâmico, detetar e aceder a oportunidades espectrais, ou seja, bandas de frequência que não estão a ser acedidas pelos respetivos utilizadores primários num determinado momento numa determinada localização. Neste contexto, os utilizadores secundários devem ser capazes de analisar o espectro rádio com precisão e, de preferência, possuírem mecanismos de aprendizagem baseados em observação local e experiência passada. Apesar da área de Rádio Cognitivo ter implicações na totalidade das camadas das pilhas protocolares de comunicação, os seus problemas fundamentais localizam-se nos níveis físico (PHY) e de controlo de acesso ao meio (MAC). Em particular, os protocolos de controlo de acesso ao meio desempenham um papel fundamental no âmbito de operações de controlo de acesso ao espectro rádio e de suporte à cooperação entre utilizadores secundários. Os utilizadores primários, quanto a eles, devem manter-se abstraídos das operações de Rádio Cognitivo e, em consequência, não estarem sujeitos a qualquer tipo de alteração em cenários de Rádio Cognitivo. Esta tese apresenta cinco contribuições, essencialmente relacionadas com o nível do controlo de acesso ao meio, com o objetivo de incrementar os níveis de proteção dos utilizadores primários e de desempenho dos utilizadores secundários em redes de Rádio Cognitivo distribuídas, especialmente quando os utilizadores secundários não têm antecipadamente acesso a qualquer tipo de informação, tal como a localização de utilizadores primários. Neste tipo de cenário, não existe qualquer entidade central responsável por recolher e processar dados de origem diversa ou tomar decisões de acesso ao espectro rádio. Ou seja, as soluções propostas adequam-se a utilizadores secundários que operam de um modo autónomo e cooperativo. Estes tomam as suas decisões baseando-se, essencialmente, em observações locais, em eventuais resultados de aprendizagem e em dados trocados entre si. A primeira contribuição desta tese consiste numa descrição da área de Rádio Cognitivo através de um estado da arte detalhado. A segunda contribuição resulta na definição de um protocolo de controlo de acesso ao meio apoiado num mecanismo inovador, designado COSBET (Cooperative Sense-Before-Transmit), que oferece um nível superior de proteção dos utilizadores primários em cenários de Rádio Cognitivo distribuídos sujeitos ao problema do utilizador primário oculto. Este tipo de anomalia ocorre quando um utilizador secundário é incapaz de detetar as atividades de um determinado utilizador primário apesar de poder provocar interferências na respetiva área de abrangência. Tal como já foi referido, na área de Rádio Cognitivo, é considerado desejável os utilizadores secundários terem capacidades de aprendizagem baseadas em observação local e experiência passada. No entanto, em cenários distribuídos, o problema do utilizador primário oculto afeta negativamente a qualidade dos resultados de aprendizagem obtidos e, em consequência, o nível efetivamente alcançado em termos de proteção dos utilizadores primários. Sendo assim, esta tese também analisa esta questão e propõe uma solução destinada a tratá-la, estando esta terceira contribuição baseada num conceito chave designado FIBASC (Filtering Based on Suspicious Channels). A troca de informação de controlo em redes de Rádio Cognitivo distribuídas é frequentemente suportada por um canal partilhado e acessível à globalidade dos utilizadores secundários. Este é o designado canal de controlo comum (CCC), sendo igualmente esta a abordagem seguida pelo protocolo COSBET-MAC proposto. No entanto, os CCC estão sujeitos a problemas de saturação. A ocorrência deste tipo de problema impede os utilizadores secundários de tirarem pleno proveito das potencialidades oferecidas pelo Rádio Cognitivo, acabando por limitar os níveis de desempenho de comunicação alcançáveis. Sendo assim, nesta tese também analisamos esta questão e propomos uma solução destinada a abordá-la, correspondendo esta à nossa quarta contribuição. A solução proposta, designada CORHYS (Cognitive Radio Hybrid Signalling), baseia-se num esquema de sinalização híbrido que recorre simultaneamente a um CCC e aos canais de dados que vão sendo alocados de forma dinâmica. A quinta e última contribuição desta tese consiste na definição de uma estratégia adicional, igualmente localizada no nível do controlo de acesso ao meio, destinada a melhorar o desempenho dos utilizadores secundários em cenários de Rádio Cognitivo distribuídos em que se recorre a um CCC. Fazem parte das suas linhas orientadoras a otimização da reutilização espacial do espectro rádio e a redução do tráfego de controlo gerado entre utilizadores secundários. As soluções de Rádio Cognitivo propostas no âmbito desta tese foram avaliadas em ambiente de simulação, sendo esta uma prática comum, nomeadamente devido a limitações de tempo e de outros tipos de recursos. Para o efeito, recorreu-se ao OMNET++ (Objective Modular Network Testbed in C++), um simulador baseado em eventos discretos e de código aberto. A totalidade das contribuições da presente tese podem ser aplicadas em conjunto. A integração destas deu origem a uma solução única e otimizada de controlo de acesso ao meio destinada a cenários de Rádio Cognitivo distribuídos. Esta aborda as duas principais preocupações existentes em cenários de Rádio Cognitivo: proteger os utilizadores primários de qualquer tipo de interferência prejudicial; e melhorar o desempenho de comunicação dos utilizadores secundários. Tanto quanto sabemos, as várias soluções propostas e o nível de completude que a utilização conjunta destas permite não são oferecidos por qualquer outra proposta de controlo de acesso ao meio existente para cenários de Rádio Cognitivo distribuídos. As contribuições desta tese também apontam direções que podem ser seguidas no âmbito de outros protocolos de controlo de acesso ao meio, especialmente aqueles que se destinam a redes de Rádio Cognitivo distribuídas.The radio spectrum has been statically regulated, i.e., essentially partitioned into licensed frequency bands, which are accessed exclusively by authorized users, and unlicensed frequency bands that can be freely accessed. Due to this inflexible policy, large portions of the entire radio spectrum remain unused independently of time and location in the world, while some frequency bands suffer from increasing levels of saturation, particularly the unlicensed ones in densely populated areas. Cognitive Radio (CR) is a recent paradigm that aims at improving efficiency regarding spectrum utilization. Its principles consist in allowing unlicensed wireless devices (i.e., secondary users) to access licensed frequency bands provided that the respective incumbent users (i.e., primary users) do not suffer any harmful interference. The most preponderant CR approach consists in having a secondary user (SU) dynamically locating and accessing spectrum opportunities, i.e., frequency bands that are not being accessed by any primary user (PU) at a given time and location. Consequently, sensing the spectrum and learning through local observation and past experience, which enables proactive spectrum decision, are key CR issues. Despite CR has implications in all the layers of the communication protocol stack, its fundamentals are mainly related to the physical (PHY) and medium access control (MAC) levels. In fact, CR MAC protocols are at the heart of spectrum access control and cooperation between SUs. PUs are expected to be unware of CR operations and, consequently, should not suffer any modification under CR scenarios. This thesis provides five contributions, essentially related to the MAC level, with the aim of improving the protection of PUs and the communication performance of SUs in cooperative distributed CR networks, particularly when there is no access to any a priori known information, such as the locations of primary transmitters. In this type of scenario, there are no central entities that collect and fuse data, or take spectrum decisions. That is, the proposed solutions fit into totally autonomous and cooperating SUs, i.e., SUs that take their own decisions based on local observation, on learning outcomes if any is available, and on data they exchange with each other. The first contribution of this thesis consists in a description of the CR area through an indepth state of the art. The second contribution lies in the definition of a CR MAC protocol that follows a novel approach, named Cooperative Sense-Before-Transmit (COSBET), which provides a higher protection of PUs in distributed CR scenarios that suffer from the hidden PU problem. This issue occurs when a SU cannot sense the activities of a given PU despite it can cause harmful interference to its coverage area. As already mentioned, CR considers that the SUs might have learning capabilities based on local observation and past experience. However, in distributed scenarios, the hidden PU problem affects the accuracy of learning and, therefore, the effectiveness of PU protection. For that reason, in this thesis we also discuss this issue and propose a novel solution that addresses it. This solution is based on a key concept named FIBASC (Filtering Based on Suspicious Channels). Utilizing a common control channel (CCC), i.e., a channel that is available to all the SUs in a CR network, for signalling purposes is a frequent practice concerning existing distributed CR MAC solutions. It is also the solution adopted by COSBET-MAC. However, a CCC is susceptible to saturation and can, therefore, become a performance bottleneck that inhibits the SUs from taking full advantage of CR potentialities. Consequently, the fourth contribution of this thesis consists in analysing this issue and addressing it through a novel solution, which we named CORHYS (Cognitive Radio Hybrid Signalling). CORHYS is based on a hybrid signalling approach that performs signalling over the CCC and over the allocated data channels simultaneously. The fifth and last contribution of this thesis consists in a MAC-level strategy that aims at further improving the performance of SUs in distributed CR scenarios that are based on a CCC. The key guidelines for this strategy are optimizing the spatial reuse of the radio spectrum and reducing control traffic. The CR solutions that resulted from this thesis were evaluated through simulation, which is a common practice, particularly due to time and other resource restrictions. For this purpose, we used OMNET++ (Objective Modular Network Testbed in C++), an open source discrete event simulator. The contributions of this thesis can be applied jointly and were successfully integrated with each other, which resulted in an optimized CR MAC solution that addresses the two main concerns in distributed CR scenarios: protecting the PUs from harmful interference; and improving the communication performance of the SUs. To the best of our knowledge, the proposed solutions and the level of completeness that they jointly achieve are not found in any other existing distributed CR MAC proposal. We also note that they define directions that can be followed by other CR MAC protocols, particularly those that target distributed CR networks

Temperature dependent core-level photoemission study of UNiSn

UNiSn undergoes an anomalous phase transition at T-N = 47 K, at which temperature it transforms from an antiferromagnetic metal to a paramagnetic semiconductor with an energy gap similar or equal to 70 meV. In order to investigate how the electronic structure of UNiSn changes as it crosses the transition temperature, we have used the X ray photoemission spectroscopy (XPS) technique from 20 to 70 K. According to the XPS studies, the U 4f core levels are almost temperature independent while the Ni 2p core levels and the satellite structure display a weak anomaly at T-N

Multiscale architectured materials with composition and grain size gradients manufactured using high-pressure torsion

The concept of multiscale architectured materials is established using composition and grain size gradients. Composition-gradient nanostructured materials are produced from coarse grained interstitial free steels via carburization and high-pressure torsion. Quantitative analyses of the dislocation density using X-ray diffraction and microstructural studies clearly demonstrate the gradients of the dislocation density and grain size. The mechanical properties of the gradient materials are compared with homogeneous nanostructured carbon steel without a composition gradient in an effort to investigate the gradient effect. Based on the above observations, the potential of multiscale architecturing to open a new material property is discussed.111010Ysciescopu

Successive spin-flop transitions of a Neel-type antiferromagnet Li2MnO3 single crystal with a honeycomb lattice

We have carried out high magnetic field studies of single-crystalline Li2MnO3, a honeycomb lattice antiferromagnet. Its magnetic phase diagram was mapped out using magnetization measurements at applied fields up to 35 T. Our results show that it undergoes two successive meta-magnetic transitions around 9 T fields applied perpendicular to the ab plane (along the c* axis). These phase transitions are completely absent in the magnetization measured with the field applied along the ab plane. In order to understand this magnetic phase diagram, we developed a mean-field model starting from the correct Neel-type magnetic structure, consistent with our single crystal neutron diffraction data at zero field. Our model calculations succeeded in explaining the two meta-magnetic transitions that arise when Li2MnO3 enters two different spin-flop phases from the zero field Neel phase.open1187Nsciescopu

Experimental studies of strong dipolar interparticle interaction in monodisperse Fe3O4 nanoparticles

Interparticle interaction of monodisperse Fe3 O4 nanoparticles has been experimentally investigated by dispersing the nanoparticles in solvents. With increasing the interparticle distances to larger than 100 nm in a controlled manner, the authors found that the blocking temperature (TB) of the nanoparticles drops continuously and eventually gets saturated with a total drop in TB of 7-17 K observed for 3, 5, and 7 nm samples, compared with their respective nanopowder samples. By carefully studying the dependence of TB on the interparticle distance, the authors could demonstrate that the experimental dependence of TB follows the theoretical curve of the dipole-dipole interaction. © 2007 American Institute of Physics.open313

Nemo: a computational tool for analyzing nematode locomotion

The nematode Caenorhabditis elegans responds to an impressive range of chemical, mechanical and thermal stimuli and is extensively used to investigate the molecular mechanisms that mediate chemosensation, mechanotransduction and thermosensation. The main behavioral output of these responses is manifested as alterations in animal locomotion. Monitoring and examination of such alterations requires tools to capture and quantify features of nematode movement. In this paper, we introduce Nemo (nematode movement), a computationally efficient and robust two-dimensional object tracking algorithm for automated detection and analysis of C. elegans locomotion. This algorithm enables precise measurement and feature extraction of nematode movement components. In addition, we develop a Graphical User Interface designed to facilitate processing and interpretation of movement data. While, in this study, we focus on the simple sinusoidal locomotion of C. elegans, our approach can be readily adapted to handle complicated locomotory behaviour patterns by including additional movement characteristics and parameters subject to quantification. Our software tool offers the capacity to extract, analyze and measure nematode locomotion features by processing simple video files. By allowing precise and quantitative assessment of behavioral traits, this tool will assist the genetic dissection and elucidation of the molecular mechanisms underlying specific behavioral responses.Comment: 12 pages, 2 figures. accepted by BMC Neuroscience 2007, 8:8

Informal Action—Adjudication—Rule Making: Some Recent Developments in Federal Administrative Law

Direct energy consumption of ICT hardware is only “half the story.” In order to get the “whole story,” energy consumption during the entire life cycle has to be taken into account. This chapter is a first step toward a more comprehensive picture, showing the “grey energy” (i.e., the overall energy requirements) as well as the releases (into air, water, and soil) during the entire life cycle of exemplary ICT hardware devices by applying the life cycle assessment method. The examples calculated show that a focus on direct energy consumption alone fails to take account of relevant parts of the total energy consumption of ICT hardware as well as the relevance of the production phase. As a general tendency, the production phase is more and more important the smaller (and the more energy-efficient) the devices are. When in use, a tablet computer is much more energy-efficient than a desktop computer system with its various components, so its production phase has a much greater relative importance. Accordingly, the impacts due to data transfer when using Internet services are also increasingly relevant the smaller the end-user device is, reaching up to more than 90 % of the overall impact when using a tablet computer.QC 20140825</p

Bulk properties of the van der Waals hard ferromagnet VI3

We present comprehensive measurements of the structural, magnetic, and electronic properties of layered van der Waals ferromagnet VI3 down to low temperatures. Despite belonging to a well-studied family of transition-metal trihalides, this material has received very little attention. We outline, from high-resolution powder x-ray diffraction measurements, a corrected room-temperature crystal structure to that previously proposed and uncover a structural transition at 79 K, also seen in the heat capacity. Magnetization measurements confirm VI3 to be a hard ferromagnet (9.1 kOe coercive field at 2 K) with a high degree of anisotropy, and the pressure dependence of the magnetic properties provide evidence for the two-dimensional nature of the magnetic order. Optical and electrical transport measurements show this material to be an insulator with an optical band gap of 0.67 eV - the previous theoretical predictions of d-band metallicity then lead us to believe VI3 to be a correlated Mott insulator. Our latest band-structure calculations support this picture and show good agreement with the experimental data. We suggest VI3 to host great potential in the thriving field of low-dimensional magnetism and functional materials, together with opportunities to study and make use of low-dimensional Mott physics

Tailoring force sensitivity and selectivity by microstructure engineering of multidirectional electronic skins

Electronic skins (e-skins) with high sensitivity to multidirectional mechanical stimuli are crucial for healthcare monitoring devices, robotics, and wearable sensors. In this study, we present piezoresistive e-skins with tunable force sensitivity and selectivity to multidirectional forces through the engineered microstructure geometries (i.e., dome, pyramid, and pillar). Depending on the microstructure geometry, distinct variations in contact area and localized stress distribution are observed under different mechanical forces (i.e., normal, shear, stretching, and bending), which critically affect the force sensitivity, selectivity, response/relaxation time, and mechanical stability of e-skins. Microdome structures present the best force sensitivities for normal, tensile, and bending stresses. In particular, microdome structures exhibit extremely high pressure sensitivities over broad pressure ranges (47,062 kPa(-1) in the range of &lt; 1 kPa, 90,657 kPa(-1) in the range of 1-10 kPa, and 30,214 kPa(-1) in the range of 10-26 kPa). On the other hand, for shear stress, micropillar structures exhibit the highest sensitivity. As proof-of-concept applications in healthcare monitoring devices, we show that our e-skins can precisely monitor acoustic waves, breathing, and human artery/carotid pulse pressures. Unveiling the relationship between the microstructure geometry of e-skins and their sensing capability would provide a platform for future development of high-performance microstructured e-skins